Process for purifying coal or other gases



Patented Apr. 9, 1929.

' UNITED ,STATES' PATENT oFFlcE.

J OSEPE NEWELL BEESON, OI MELBOURNE, YIC'lIORIA, AND WILLIAM LANGELOTMOSS,

on cmnnnwnm..v1crom, Aos'rmu.

PROOESSIOR PUBIFYIING COAL OR OTHERiGASES.

No Drawing.

This invention has been devised to provide a process for purifying gasi. e. the removal therefrom of particularly hydrogen sulphide,'bisulphide of carbon, thiohydrocarbons and 5 cyanogen compounds. 4 I

The invention is particularly useful for treating coal gas, and will bedescribed herein in reference thereto, but it is to be understood thatthe use of the invention is not lim- 0 ited thereto, as it may beapplied to any gases containing hydrogen sulphide and other'sulphidecompounds, such as industrial gases, blast furnace gases and all wastegases from any process. v In-view of the departure from the acceptedpractice of the present invention, and the vast importance of theresults obtained thereby, it is necessary to make a full disclosure andhave a proper understanding of the significance of the process for thepurifying of coal or other gases hereinafter described to premise thedescription of the process by clearly indicating the nature of theproblems involved.

The present means employed in the purification of coal gas, consists inthe employment .of purifiers comprising large rectangular boxessulficiently deep to hold several layers of purifying material, usuallyhydrated oxide of iron, and during treatment, it is necessary from timeto time that the oxide be removed from the purifier and exposed to theoxygen of the air by turning it over and allowing it free access toit,such operations cause considerable expense and waste of time,-both"greatly adding to the cost ofproduction, and further the cost ofinstallation and renewal of such apparatus is very large.

. Our invention overcomes the foregoing dis- 40 advantages by providinga process in which the gas is purified as required in a simple,expeditious and thorough manner.

Another object of this invention is to provide a process for thepurification of gas,

whereby during treatment the impurities from the gas are recovered in acondition suitable for commercial purposes.

Another object of this invention is to provide a process for thepurification of coal or other gases, whereinthe purifying solution isregenerated to render it fit'for further use. Another object of thisinvention is to provide -a process for, the purification of coal orother gases, wherein the purifyin solution is prepared in a formsuitable or gas Application filed March 13, 1925, Ser'1al No. 15,840,and in Australia April 80, 1924.

purification purposes, as hereinafter described.

Another object of this invention is to provide a process for thepurification of coal or other gases, wherein during the process thesulphuris recovered in its elementary condition as hereinafterspecified.

Another object of this invention is to provide a process for thepurification of coal or other gases, wherein during the process thecyanogen compounds are recovered as hereinafter described.

A further object of this invention is to provide a process for thepurification of gas, whereby the treatment is carried out and the plantnecessary therefor may be installed and operated at a small cost incomparison with that incurred with the present means used for thepurification of gas. In addition the regeneration of the purifyingsolution is accomplished.

Our invention is as follows We provide a number of suitable vesselsarranged in any desired manner, the' gas is passed through such vessels,and in doing so comes into contact with and is washed by a liquidcontained therein,such liquid being an alkaline solution of ironhydsqxide.

In the preparation of the said solution an iron compound is used,preferably the sulphate or the chloride, to which has been added anysubstance having the property of precipitating iron such as the hydratesor carbonates of potassium sodium, or ammonium and organic bases such aspyridine and quinoline and the like.

An essential feature of this invention is that in the preparation of thesolution of iron hydroxide, substances having a solvent action inneutral 'or alkaline solution on hydrate of iron are employed, such forinstance as salicylic acid, para hydroxybenzoic acid and phthalic acidand their alkali metal salts, polyatomic alcohols and their. derivativesincludin' theglycols and glycerine, citric acid an citrates, isomers oftartaric acid and their alkali metal salts.

' Durin the process of purification, the preparedsol ution of ironhydroxide-absorbs hydrogen sulphide; and cyanogen compounds are absorbedas ferrocyanide and carbonyl ferrocyanide, and further, the bisulphideof carbon and thiophene are removed partly by the suspended sulphurobtained. during the regeneration of the solution and partly as rocessof purification and lie performed continuously desired.

When' regeneration of the solution is necessary this can be accomplishedby aeration by means of air or oxygen at a low or high temperature andpreferably under pressure. In regeneration the. air'exerts an oxidizingaction and causes a. deposition of sulphur which "remains in suspensionand formation of polythlonic aclds whlch consume a ortlon of the alkaliused and the iron puri ing solution 7 1s reformed and oxidized and isthen ready I washing liil uor.

nmbefore mentioned chemicals or the various.

' kali is added in quantity su for further treatment of as. -Furtheralicient to keep the solution neutral or alkaline and further iron saltto replace that consumed by the cyanogen compounds. -'The sulphur can beremoved and further treated as required. Cyanogen compounds graduallyaccumulate in the' washingliquor-which is ultimately treated to recoverboth these and the sulphur acids, as saleable salts, WhichIffindisefficiently accomplished d have it understood that we do We won notarbitrarily confine ourselves to .the here:

steps arranged in the process, as they'may be varied for the particularpurpose, without 'de arting from'the nature of our imnention.v

eclam1:- 1. A solutionforpurifymg gas contalnmg H 3 and other impuritiesformed by o0mbin-' ing a base, 2. Inja process for purifying gascontain:

an'iron salt, and citric acid. 1

taining iron hydroxide and citric by' evaporation of the 7. In-a'processfor,

ing H 8 and other frities, treating the an as witha non-acidic solutioncon ydroxide of theiron family and citric acid. j

- 3. In the .rocess of purifying. containing H,S and other impurities,su 'ecting the gas to the action of a non-acidic so utiipn conacl . 4.In a process for purifying containing H S and other impurities, sujecting the gas to the action of a solution con iron hydroxide, a base,and citric acid.

5. In a process for purifying. as containing H S' and other impurities,

a base, iron hydroxide,

su jecting the gas to the action of a solution containing and a solventfor' said hydroxide, the said solution acting to absorb carbonbisulphide, thiocarbons, hy rocyanic. acid and cyanogen compounds, fromthe gas, the said solution by subjecting it to aeration by means of airor oxygen, under pressure.

6. In the process for hydrogen suliphide,

the gas with a solution formed by combining .a base and iron salt, ahydroxide, solution in suflicient.

amounts of said base and salt to replace that consumed during washing ofthe gas and the V cyanogen compounds there- 1 absorption of from, andregenerating the foul solution by aeration with air under presureresulting in reformation'of the hydroxide and recovery'ofthe sulphidesabsorbed from the gas as elemental sulphur.

ing H,S and other gas with a solution an iron salt, and a solvent forthe resultant hydroxide continuously by passing the gas impurities,treating the and regenerating purifying gas contaming H S-and otherimpurities, washing solvent for the resultant and continuouslyadding tosuch quantity further purifying gas contain-1 comprising a base andthrough the solution and continuously re-Q generating the solution withair under pressure; I

In testimony whereof we have names to this specification. r

JOSEPH NEWELL REESON. U LANCELOT MOSS.

signed our:

